Acta Crystallographica Section C

Crystal Structure Communications

Volume 69, Part 8 (August 2013)

organic compounds

sk3500 scheme

Acta Cryst. (2013). C69, 927-933    [ doi:10.1107/S0108270113017538 ]

Two polymorphs of N-(2-methoxyphenyl)-4-oxo-4H-chromone-3-carboxamide

L. R. Gomes, J. N. Low, F. Borges and F. Cagide

Abstract: The title compound, C17H13NO4, crystallizes in two polymorphic forms, each with two molecules in the asymmetric unit and in the monoclinic space group P21/c. All of the molecules have intramolecular hydrogen bonds involving the amide group. The amide N atoms act as donors to the carbonyl group of the pyrone and also to the methoxy group of the benzene ring. The carbonyl O atom of the amide group acts as an acceptor of the [beta] and [beta]' C atoms belonging to the aromatic rings. These intramolecular hydrogen bonds have a profound effect on the molecular conformation. In one polymorph, the molecules in the asymmetric unit are linked to form dimers by weak C-H...O interactions. In the other, the molecules in the asymmetric unit are linked by a single weak C-H...O hydrogen bond. Two of these units are linked to form centrosymmetric tetramers by a second weak C-H...O interaction. Further interactions of this type link the molecules into chains, so forming a three-dimensional network. These interactions in both polymorphs are supplemented by [pi]-[pi] interactions between the chromone rings and between the chromone and methoxyphenyl rings.

Formula: C17H13NO4 and C17H13NO4

Keywords: crystal structure; polymorphs; pharmaceutical compounds; molecular conformation.

hkldisplay filedownload file

Structure factor file (CIF format) (362.9 kbytes)
[ doi:10.1107/S0108270113017538/sk3500Isup2.hkl ]
Contains datablock I

hkldisplay filedownload file

Structure factor file (CIF format) (216.1 kbytes)
[ doi:10.1107/S0108270113017538/sk3500IIsup3.hkl ]
Contains datablock II


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